Reformatting the hard drive will remove the previous owner's info, files, and installed programs, BUT it will also remove the operating system. Do you have a way of re-installing Vista or some other operating system?
You could check if that particular model of Dell computer has a hidden factory recovery partition on the hard drive. If it has it, then it would be able to restore the remainder of the hard drive to factory fresh conditions. It would be missing all updates to Vista since the day it was made.
You could check if that particular model of Dell computer has a hidden factory recovery partition on the hard drive. If it has it, then it would be able to restore the remainder of the hard drive to factory fresh conditions. It would be missing all updates to Vista since the day it was made.